1640-1658 - First recorded contact with the Dakota tribes of the Sioux by Jesuits in the area of present-day Green Bay, Wisconsin, and in the forests in southern Minnesota.

1775 - The Continental Congress establishes a Committee on Indian Affairs, appointing commissioners to create peace treaties with the Indians.

1803 - Louisiana Purchase brings a greater number of trading posts into Indian Territory. As a result, fur trading becomes an important part of Oglala Indian life, expanding the Lakota influence as far west as the Big Horn Mountains in Wyoming and south to the Platte River in Nebraska.

1804 - The Sioux and other tribes encounter the Lewis and Clark expedition.

1817 - American traders began to compete with Native American tribes for the buffalo fur business.

1825 - A treaty is established between the U.S. and the Oglala branch of the Teton Sioux (Lakota) regarding fur trade, signed for the Oglala by Standing Buffalo (aka Standing Bull). The 1825 treaty states that the Sioux and Oglala "...reside within the territorial limits of the United States, acknowledge their supremacy, and claim their protection. The said bands also admit the right of the United States to regulate all trade..."

1830 - The Indian Removal Act forces Native Americans living east of the Mississippi River to abandon their homes and move into the newly established Indian Territory to the west. The Cherokee tribe resists and sues the U.S. They are granted the right to stay on their land in two key Supreme Court cases, however, President Andrew Jackson ignores the court order and sends troops in to force Cherokee removal.

1834 - Four thousand Oglala people relocate to Fort Laramie to boost their fur trade with white people.

1838 - Over 18,000 Cherokees are forcibly removed from their land and resettled west of the Mississippi, in what is referred to as the "Trail of Tears."

1840s - An increasing flow of emigrants to Oregon and California bring cholera, smallpox, and measles to the Indians as well as accelerated buffalo hunting for the fur trade.